CVE-2021-3431

BT: Assertion failure on repeated LL_FEATURE_REQ

4.3 Medium

Assertion reachable with repeated LL_FEATURE_REQ. Zephyr versions >= v2.5.0 contain Reachable Assertion (CWE-617). For more information, see https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-7548-5m6f-mqv9

Attack profile

How easy it is to exploit

Attack vector: Adjacent network
Complexity: Low
Privileges needed: None
User interaction: None

What an attacker can affect

Confidentiality: None
Integrity: None
Availability: Low

Exploit likelihood

0.92%Unchanged since Jun 29, 2022

What each source reports

CVE List Score used 4.3

BT: Assertion failure on repeated LL_FEATURE_REQ

Record: CVE-2021-3431
CVSS 3.1: 4.3 MediumCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Weakness: CWE-617
Updated: 2026-11-02

EUVDEUVD-2021-26757 4.3

Record: EUVD-2021-26757
CVSS 3.1: 4.3 MediumCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Updated: 2026-11-03

NVD 4.3

Record: CVE-2021-3431
CVSS 3.1: 4.3 MediumCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
CVSS 3.1: 7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CVSS 2.0: 5.0 MediumAV:N/AC:L/Au:N/C:N/I:N/A:P
Weakness: CWE-617
Updated: 2026-11-02

Affected products

History

History
Recorded	Changed	Sources
Nov 3, 2026	aliases, published	EUVD
Nov 2, 2026	first indexed	CVE List, NVD

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2021-3431 is a medium vulnerability (CVSS 4.3) in Zephyrproject Zephyr, published June 28, 2022. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.92%, the 60th percentile. No source names a fixed version.

References

github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-7548-5m6f-mqv9